Cross-roll grinding apparatus



April 2, 1957 D. F. KEELER CROSS-ROLL GRINDING APPARATUS 3 Sheets-Sheet 1 Filed Aug. 4. 1955 April 1957 D. F. KEELER 2,787,091

CROSS-ROLL GRINDING APPARATUS Filed Aug. 4. 1955 3 Sheets-Sheet 2 H INVENTOR.

Dav/up /-I' 165554 42/ April 2, 1957 D. F. KEELER CROSS-ROLL GRINDING APPARATUS 3 Sheets-Sheet 3 Filed Aug. 4. 1955 Y INVENTOR. @Msw f. /4 e 2 BY i l I;

United States Patent CROSS-ROLL GRINDING APPARATUS Donald F. Keeler, Bellefonte, Pa., assignor to Sutton Engineering Company, Bellefonte, Pa., a corporation of Pennsylvania Application August 4, 1955, Serial No. 526,364

7 Claims. 01. s1--9s This invention relates to apparatus for grinding crossrolls and the like to an approximate hyperboloid and 1s particularly applicable to grinding the cross-rolls used in machines for straightening round bars or tubes.

In such machines, two or more cross-rolls are angularly disposed to each other and the stock to be straightened is passed between the rolls. Ideally, the cross-rolls should have a contour that will permit the cylindrical surface of the stock being straightened to intersect each roll in a substantially straight line along the entire working length of the roll face. As the diameter of the stock approaches zero, this ideal roll contour tends to become a hyperboloid. On the other hand, as the diameter of the stock increases towards infinity, the ideal roll contour approaches a cylinder. Between these two extremes, the roll contour is a curve of revolution that can be expressed only by very complex equations; but for practical purposes, in which the stock to be straightened has a small diameter relative to that of the rolls themselves, this contour approximates a hyperboloid. Heretofore, the contouring of such rolls,

both initially and after a roll has been worn, has been done by using a grinding wheel of large diameter compared to the diameter of the stock being straightened, and of short length compared to the length of the work face of the roll. As a result, only a small portion of the roll face can be ground at one time; and the axis of the grinding wheel must be set at an angle to the axis of the roll that is different from the angle between the smaller bar stock and the roll when the machine is in use, with corresponding inaccuracy in the contour of the roll.

It is accordingly among the objects of this invention to provide a grinding apparatus of the type referred to, in which the resulting contour of the roll face will provide substantially straight line contact between that face and the stock to be straightened when the latter is passed through two or more crossrolls, in which the entire work face of the roll is contacted by the grinder during the grinding operation, and in which the time required for contouring a roll is greatly reduced over What is now conventionally required.

In accordance with this invention, the grinder is an elongated cylinder with an abrasive surface and with a diameter substantially equal to that of the stock to be passed between the rolls. The grinder and roll are both rotatably mounted in separate supports with their axes spaced from and angularly disposed to each other, so that a common line perpendicular to both axes will intersect the roll axis midway between its ends. Means are provided for moving the grinder and the roll relative to each other in a plane including this common line, so as to maintain grindingcontact without changing the angular disposition of the respective axes. In addition, means may be provided for varying the angle between the roll and grinder axes and for reciprocating either the grinder or the roll along a line parallel to the grinder axis to prevent uneven wearing of the grinding surface.

A preferred embodiment of the invention in the attached drawings, in which Fig. 1 is a perspective view of the invention;

Fig. 2, a front elevation, partly in section; and

Fig. 3, an end elevation, partly in section.

is illustrated Referring to the drawings, the roll grinding apparatus 1 includes a bed 1 secured to a suitable foundation or support. A base 2 is slidably mounted on this bed; and i movement of the base thereon, other than reciprocal,

movement in a given direction, is prevented by engaging with a collar 12, engaging a dog 13 on the shaft for rotating the latter through pulleys 14 and 15, belt 16, l

and motor 17. Preferably, the base 2 is provided with means, such as a rack 20 and pinion 21, for reciprocating it on the bed 1. The pinion is driven by a motor 22 through a reduction gear 23 and a spur gear 24. Motor 22 is reversible and is reversed through limit switches (not shown) mounted on each end of the bed and actuated by contact with the base at each end of its travel.

In a plane at right angles to the longitudinal axis of the bed 1, and like the bed secured to a suitable foundation or support, is a frame 29. It includes columns 30 and a cross member 31. Suspended from this cross member is a grinder support 32, with inverted rollshaft supports 33, in which is rotatably mounted a grinder 34. This grinder is in the form of an elongated cylinder and has an abrasive coating. Its diameter is preferably the same as that of the round stock tobe introduced for straightening between the cross machine. By using a grinder of that diameter, the rolls will be perfectly contoured for a particular size of stock. In cases where the machine is to be used with different rolls of a straightening sizes of stock by varying the spacing and angularity of the rolls, it will be desirable to select a grinder having a diameter approximating the average diameter of the stock to be straightened. The grinder itself may be made in one piece or in sections, such as from sleeves of abrasive, or abrasive coated material, placed end to end over a shaft to which the sleeves are suitably keyed. The grinder is rotated by a separate motor 40 through a belt 41 and pulleys 42 and 43. Preferably, its direction of rotation is counter to that of the roll; but, if desired, it can be rotated in the same direction.

The grinder support is disposed at right angles to the cross member of the frame and can be adjusted longitudinally of that member by means of the: sliding block 44, to which the support is attached. This block is supported in a horizontal slide 45 on the cross member and is adjusted therein by a screw 46. The slide 45 can also be adjusted vertically on the cross member by means of screws 47 and 48, which actuate blocks 49 and 50 in vertical slides 51 and 52. The latter are rigidly attached to the cross member. The foregoing slide adjustments enable the grinder to be properly positioned over the surface of the roll and tact with the roll, as hereinafter explained.

The roll is preferably mounted in the roll support so that the mid-point of the roll is directly over the pivot 6. In other words, the axis of that pivot preferably intersects the axis of the roll at a point midway between the ends of the roll. The grinder, in turn, would then This to be maintained in grinding conbe positioned so that its axis intersects the axis of the pivot. Such mounting and positioning assure symmetrical grinding of the roll on either side of its midpoint, which is the point of least diameter.

In practice it 'is-often difficult to mount'the roll so that its midpoint coincides with the axis of the pivot, without providing means for adjusting the rolllongitudinally in the 'IOllStlppOYt. But such-precise mountingis unnecessary in view of the adjustment that can be made in the position of-thegrinder longitudinally of the cross member 31--by means of the screw 4.6. By. this latter a justment, the axis of the grinder can be in theposition directly above the axis'of the roll at, the midpoint of the latter, regardless "of where the pivot 6 is located.

While the embodiment ofjthe invention shown in the drawings discloses means for reciprocating the roll in a lineparallel to the axis of the grindenit will be readily understood'that the desired relative reciprocal motion between the grinder androll couldalso be obtained by making the roll support stationary and reciprocating the grinder, either by'movement of the grinder support, or by movement of'the grinder itself in that support, in a directionparallel to the grinder axis.

In operation, the grinder and'roll are positioned as above described, andthe angle between the axes of the roll; and grinder is adjustedin accordance with the de sired contour ofthe roll. The grinder is then brought into contact with the working face of the roll, and both roll and grinder are rotated. If one were to start initially with a cylindrical roll and shaped it to the desired contour entirely by grinding, there would at first beonly point contact between the roll and grinder. As grinding proceeded and the roll surface became more concave, this point contact extends into line contact, with the line becoming increasinglylonger. When the grinding is completed, there is straight line contact betweentheroll and grinder along the entire working face of. the roll. Ordinarily, rolls are rough cast and/ or machined to approximatetheir ultimate contour before they are ground, so that there is a substantial linear contact between the grinder and roll from the beginning of the grinding operation. Thesame initial contact also prevails in regrind: ing worn rolls. If the grinder and roll were not reciprocated relativeto one another parallel to the axis of the grinder during the grinding operation, the grinder would become worn'at points where the roll surface was initially high. However, the reciprocatingmotion between those two elements causes the roll to move back and. forth parallel to'the axis of the grinder, so that inequalities and irregularities in the surface of the grinder do not develop, and it is worn uniformly.

It is among the advantages of this invention that it provides ameans for grinding the cross-rolls of a straightening machine, or the like, to a substantially hyperbolic contour that will provide straight line contact between the:.rolls and bar stock to be processed therein when the grinder and stock have the same diameter, and substantially straight line contact when those diameters difier. In addition, the grinder can beset atthe same angle ,tothe roll during the grinding operation as will exist between,the stock. and the roll in later straightening operations, thereby avoiding those inaccuracies in the contour-of'the roll that are obtained where the grinder is of a substantially different. diameter than the wor piece. Furthermore, during the. grinding operation there is contact between the grinderand substantially the entire working face of the roll, which greatly reduces the grinding time.

Accordingto the provisions of the patent statutes, I have explained the principle of my invention and have illustrated and described What I now consider; to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. Apparatus for contour grinding'a cross-roll of a bar straightening machinetandthe. like, comprising a roll support on which aroll isrotatably mounted, an elongated cylindrical grinder having a diameter substantially equal to that of the, bar to be straightened,.means for rotatably supporting the grinder in contactwith the roll face and with its axis at an angle to the axis of theroll and so positioned that a common perpendicular. to both. axes will intersect the roll axis at its midpoint, and means for rotating the grinder-and roll. about their respective axes.

2. Apparatus in accordance with claim 1, and including means for effecting relative reciprocationybetweenthe grinder and rollina directionparalljel, tothe axis. of the grinder.

3. Apparatus in accordance,witlrclaim. 1, and including means for adjusting the. anglebetween the roll. and grinder axes.

4. Apparatus for contour grinding a: cross-roll to an approximate hyperboloid, comprising a roll support in which the roll is rotatably mounted, an elongatedcylindrical grinder having a diameter substantially equal to that iof'material'to be rolled, agrindersupport in which the grinder is rotatably mounted with its; axis spacedfrom and angularly disposedto the; axis of the roll with the grinder in contact with. a midpoint of the roll face, means for varying the angular. disposition of the roll and grinder axes, means for varying,v the distancebetween saidiaxes without changing their angular. disposition, and

means for rotating theroll and grinderabouttheir respec tive axes.

5. Apparatus in accordance with claim 4, which includes means for effecting relative reciprocation between the grinder and roll'in. a direction parallel to-theaxis of the grinder.

6. Apparatus according to claim 4, inwhich the length of the grinder is greater thanthe length of the roll.

7. Apparatus for contour grindingv a cross-roll to an approximate hyperboloid, comprising a stationary bed, a-

base .slidably mounted. on ,the. bed, .aroll supportpivotally mountedon the base androtatably supporting-=the.-roll, the axis ofthe pivot intersecting. theaxis of the-roll at a point midway between the ends of the roll, means for reciprocating the base on the bed, a crossmemberat.

right angles to the bedandspaced therefrom, a grinder roll and grinder, and means for rotating the grinder and.

roll about their; respective axes.

References Cited in the filctof. this: patent UNITED STATES PATENTS- 1,401,961 Coryell Jan. 3,, 1922,

2,187,471 Hutchinson- 1 Jan. 16, 1940,

2,196,108 Dunbar-et al Apr. 2', 193- 10 FOREIGN PATENTS 174,789 Austria .May 11, 1953" 

